Neonatal VT

  Ventricular tachycardia (VT) is rarely seen during the neonatal period.

  Neonatal VT is seen mostly in the form of
short attacks rather than permanent VT.



Diagnostic criteria

  QRS complexes of the VT attack are only slightly wider than normal.

      Since the mass of ventricular myocardium is small in neonates, the widening is not as striking as in adults.

 
Left bundle branch block (LBBB) morphology (presumed right ventricular origin) is seen more frequently

      than right bundle branch block (RBBB) morphology (presumed left ventricular origin) in this age group.

  Neonatal VTs are usually
monomorphic.

 
Atrioventricular (AV) dissociation may be seen in some patients.

  Sometimes
1:1 retrograd ventriculoatrial (VA) conduction with retrogradely conducted P waves

      may be seen.

  When there is 1:1 retrograd ventriculoatrial (VA) conduction during sustained VT, one may be

      suspicious on the diagnosis.

      Adenosine will neither convert VT to sinus rhythm nor decrease its rate.

      Then, Adenosine may be used to turn 1:1 retrograd VA conduction to AV dissociation.

      Adenosine will decrease ventriculoatrial conduction which will turn 1:1 VA conduction into.

      AV dissociation (with an atrial rate lesser than the ventricular rate).




Etiology of Neonatal VT

  Idiopathic (most common)

  Myocarditis

  Long-QT syndrome

  Cardiac tumors

  Metabolic disorders (carnitine-acylcarnitine translocase deficiency)




Clinical significance

  Idiopathic ventricular tachycardia of the neonate usually carry a good prognosis.

  The neonates have high heart rates. Since ventricular rate during neonatal VT is very close to the

      normal neonatal heart rate, it may be difficult to realize this abnormal rhythm at first

      (
especially in the permanent form).

  Since ventricular rate during neonatal VT is very close to the normal neonatal heart rate,

      the neonates are
usually asymptomatic during the VT attack.



References

  Cardiol Young 2010;20:641-647.

  Pacing Clin Electrophysiol 1997;20:2061-2064.

  J Am Coll Cardiol 1999;33:2067-2072.

  Can J Cardiol 2010;26:e58-e61.

  Jpn Circ J 1999;63:727-728.

  BMC Pediatr 2002;2:12.

  Arch Mal Coeur Vaiss 1998;91:623-629.

  Concise guide to pediatric arrhythmias. Christopher Wren. Wiley-Blackwell. 2011.





ECG 1a. The ECG above is from a one day-old newborn with a normal ECHOcardiogram (no structural cardiac defect).
Nonsustained VT attacks are seen among normally conducted sinus beats.
Ventricular rate during the
VT attack is very close to the normal heart rate of a neonate.
The
VT beats are only slightly wider than the normally conducted sinus beats.
Dissociated P waves further support the diagnosis of VT.
Since the ventricular rate (during VT) is very close to the sinus rate in this baby (the RR intervals of the VT beats is only
40 milliseconds shorter than that of the PP intervals), it gives the apperance of 1:1 VA conduction at first glance.

Pediatric cardiologist Dr. Mahmut Gokdemir has donated the above ECG to our website.

Click here for a more detailed ECG




ECG 1b. Above is another ECG recording from the same neonate.
As in the above ECG, short attacks of neonatal VT are more frequent than the permanent form.
As in the above ECG, idiopathic neonatal VTs usually show
incomplete LBBB pattern (presumed right ventricular origin).
Dissociated P waves are also seen in the above ECG.

Pediatric cardiologist Dr. Mahmut Gokdemir has donated the above ECG to our website.

Click here for a more detailed ECG